Ember Concurrency Queue

controllers.application.js

import Ember from 'ember'
import {task, timeout} from 'ember-concurrency'

const { get, set, inject } = Ember

export default Ember.Controller.extend({
  queueService: inject.service(),
  
  init () {
    this._super(...arguments)
    set(this, 'logs', [])
  },
  log (type, message) {
    get(this, 'logs').pushObject({type, message})
  },
  
  task1: task(function * () {
    this.log('queue', 'task 1')
    yield get(this, 'queueService').queue1.perform(() => {	
      this.log('start', 'task 1')
    	return timeout(2000 + 2000 * Math.random())
    })
    this.log('done', 'task 1')
  }).enqueue(),
  
  task2: task(function * () {
    this.log('queue', 'task 2')
  	yield get(this, 'queueService').queue1.perform(() => {	
      this.log('start', 'task 2')
    	return timeout(2000 + 2000 * Math.random())
    })
    this.log('done', 'task 2')
  }).drop(),
  
  task3: task(function * () {
    this.log('queue', 'task 3')
    yield get(this, 'queueService').queue1.perform(() => {	
      this.log('start', 'task 3')
    	return timeout(2000 + 2000 * Math.random())
    })    
    this.log('done', 'task 3')
  }).drop(),
  
  task4: task(function * () {
    this.log('queue', 'task 4')
    yield get(this, 'queueService').queue1.perform(() => {	
      this.log('start', 'task 4')
    	return timeout(2000 + 2000 * Math.random())
    })    
    this.log('done', 'task 4')
  }).drop(),
  
  task5: task(function * () {
    this.log('queue', 'task 5')
    yield get(this, 'queueService').queue1.perform(() => {
      this.log('start', 'task 5')
    	return timeout(2000 + 2000 * Math.random())
    })    
    this.log('done', 'task 5')
  }).drop(),
  
  actions: {
    queueAll () {
      this.task1.perform()
      this.task2.perform()
      this.task3.perform()
      this.task4.perform()
      this.task5.perform()
    },
    clearLogs () {
      set(this, 'logs', [])
    }
  }
})

services.queue-service.js

import Ember from 'ember'
import {task} from 'ember-concurrency'

export default Ember.Service.extend({
  queue1: task(function * (callback) {
    try {
    	yield callback()
    } catch (e) {
      // prevent the queue from blowing up - is this necessary?
      // TODO: can I yield the error here?
    }
  }).maxConcurrency(3).enqueue()
})

styles.app.css

body {
  margin: 12px 16px;
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
  font-size: 12pt;
}

.queue {
  color: black;
}

.start {
  color: coral;
}

.done {
  color: blue;
}

templates.application.hbs

<h1>{{appName}}</h1>
<br>
<button onclick={{perform task1}}>Run Task 1</button>
{{if task1.isRunning 'Running'}}
<br>
<button onclick={{perform task2}}>Run Task 2</button>
{{if task2.isRunning 'Running'}}
<br>
<button onclick={{perform task3}}>Run Task 3</button>
{{if task3.isRunning 'Running'}}
<br>
<button onclick={{perform task4}}>Run Task 4</button>
{{if task4.isRunning 'Running'}}
<br>
<button onclick={{perform task5}}>Run Task 6</button>
{{if task5.isRunning 'Running'}}
<br>
<button {{action 'queueAll'}}>Run All</button>

<h3>Logs</h3>
<button {{action 'clearLogs'}}>Clear Logs</button>
<ol id="task-output">
 {{#each logs as |logItem|}}
 	<li class="{{logItem.type}}">{{logItem.type}} {{logItem.message}}</li>
 {{/each}}
</ol>

twiddle.json

{
  "version": "0.10.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.6.0",
    "ember-data": "2.6.1",
    "ember-template-compiler": "2.6.0"
  },
  "addons": {
    "ember-concurrency": "latest"
  }
}